<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://cdn.jsdelivr.net/npm/vue@2.7.14/dist/vue.js"></script>
</head>
<body>
  <div id="app">
    <div>
      <h1>{{ message }}</h1>
      <button @click="reverse">逆转世界</button>
    </div>
  </div>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        message: "HELLO, WORLD"
      },
      methods: {
        reverse() {
          this.message = this.message.split('').reverse().join('')
        }
      }
    })
  </script>
</body>
</html>